The present invention relates to ice scraping tools or bits of the type mounted on ice/snow removal vehicles, and to an ice-cutting method.
It is common to utilize vehicles to scrape ice from roadways by means of tools mounted on the vehicles. As depicted in FIG. 5, it is conventional to employ pointed tools 2 rotatably mounted in a carrier 3 that is welded on a vehicle-mounted board or blade 4, e.g., the board may be situated between the front and rear wheels F, W of the vehicle (see FIG. 8). The tools 2 project forwardly and downwardly at such an inclination that a hard pointed cutting tip 5 of the tool (e.g., a carbide tip) cuts at a negative rake angle A with reference to a normal N to the road surface (see Bergqvist et al. U.S. Pat. No. 4,784,517). Although such tools have been successfully used, they may, due to the negative characteristic of the rake angle, tend to pull themselves downwardly into the ice (i.e., they tend to be self-feeding) which can result in damage to the road surface beneath the ice.
As depicted in FIGS. 6 and 7, it has also been proposed to employ rotatable ice-scraping tools 6 each having a blunt circular scraping surface 8 which scrapes at a positive rake angle .delta.. While avoiding the self-feeding problem discussed above with reference to FIG. 5, such tools exhibit various shortcomings which are also characteristic of the FIG. 5 tool. A first of those shortcomings involves the fact that the tool shanks are inclined in an upward and rearward direction, whereby the tools tend not to ride over obstructions such as road unevenness, but rather tend to plow through the obstructions, causing damage to the tools and/or the road.
A second shortcoming stems from the fact that the hard cutting tips 9 of such tools are typically spaced apart in a direction transverse to the direction of vehicle travel D (see FIG. 6) and thereby cut spaced-apart grooves in the ice. The grooves serve an important function when used in conjunction with vehicles that disperse highway salt, because the grooves retain the salt, sheltering the salt against air currents caused by wind or passing traffic which could otherwise blow the salt off the ice. However, the salt deposited onto the areas of the ice surface situated between the grooves will not be sheltered and instead will be susceptible to being blown away.
A third shortcoming results from the use of cutting tips formed of a hard wear-resistant material, such as carbide (e.g., see also Meyers U.S. Pat. No. 4,753,299 disclosing carbide inserts on earth-working tools). A forwardly facing surface of the carbide insert is typically exposed and, due to the brittleness of the carbide material, is susceptible to being chipped in response to striking obstacles or uneven parts of the road surface.
It would be desirable to minimize or obviate problems of the above-described type.
For instance, it would be desirable to provide an ice-cutting tool which resists self-feeding, minimizes a tendency for deposited salt or sand to be blown from an ice surface, and exhibits a long life with minimal tendency for hard cutting tips to become chipped.
It would also be desirable to prove an ice-cutting mechanism and method in which the cutting tools tend to ride over obstructions such as road unevenness.
It would further be desirable to minimize the downward pressure needed to be applied to the ice-cutting tools.